I was watching a show on the Travel Channel (of all places) last night called Truthseekers. The episiode was about hauntings, following the organization ParaQuest at Chillingham Castle, and a Canadian one in a Nova Scotia house.

One of the people they had on the show, and I honestly cannot recall the gentleman's name, just that he was a professor at Coventry in the UK, theorized that some hauntings, the type where you have the senstion of being watched, see a shapless, greyish form from the corner of your eye and experience a cold sweat, hair raising and that type of sensation, is actually caused by a low frequency sound, so low it's actually beneath our hearing level.

Now, he had prior to coming to this theory, had just such an experience while working late one night, and believed himself to have had a paranormal experience. A few days later, he had placed a rapier (he practiced fencing as a hobby) in a vise to repair it and noticed that the tip was vibrating at a fairly high rate, and he began again to experience the 'haunt' that he had a few days earlier. From what I can gather, he then began investigating and discovered that a fan in a vent was the cause of it. He did some scientific work that they glossed a bit over (and I admit to not really understanding) and was able to recreate the whole thing outside of the laboratory setting.

His theory is that the low frequency sound is the cause of some types of hauntings, being that if the sound is low enough it can actually cause our eyeballs to 'dither' , causing us to see the grey shapeless form. The low frequency sound also causes us to experience the other sensations accounted for in that type of haunting. He gathered that some areas where people have reported that kind of haunt are actually emitting a low frequency sound, be it natural or through a piece of equipment on sight.

I thought it to be an interesting theory, so I thought I'd share it with you. I'm sorry I can't recall the gentleman's name, but I'll be doing some looking around and see what I can find.

Vampchick- A few days later, he had placed a rapier (he practiced fencing as a hobby) in a vise to repair it and noticed that the tip was vibrating at a fairly high rate, and he began again to experience the 'haunt' that he had a few days earlier.

In my personal opinion that specific part doesn't sound right, but the premise about low frequency waves could have something to it.

I do know that ultrasonic devices are comercially available that induce a "sick" feeling through sound. Used by rascles to disorient speakers and experimental units designed for crowd control. The military has also experimented with ultrasonics for antipersonnel weapons (capable of causing death way back to WWI). Except for black ops, not alot of info is generally available (that I have seen) about the effect of "sound" waves on people.

Well, the bit about the rapier was more or less from my not always reliable memory. I may not have recalled the whole thing correctly.

I do find it to be an interesting theory, if I could recall the man's name, it would make my search a bit easier. I guess I'll have to keep an eye out for a repeat of that episiode and write the name down.

I know electrical current "leaking" from wires is really high-pitched and some people think it's a haunting. Of course, I met someone who thought the high-pitched frequency from her old TV was the ghost of her dead son too.

Some people are very sensitive to frequencies, even though they're supposed to be out of human range. It seems pretty interesting anyway....

There's a fair bit of evidence which suggests that the Very Low Frequency sonar tested by the US Navy was responsible for causing pods of whales to strand - one reason this is of such concern is the distance over which the sonar waves travel - and, as flyorb pointed out, ultrasonics can be used to induce physically distressing symptoms in human beings (my recollection is that ultrasonics only have this effect at reasonably close range), so it is certainly possible that some reported "hauntings" might be caused by perceptual distortions brought about by commercial or military use of sound wave technology (or E-M technology in general).

I'll see what more information I can track down about the particular TV show mentioned in the OP.

The physiological effects of infra-sound were studied and recorded by NASA scientists in the mid-1970s, and they include watery eyes, visual hallucination, increased muscle tension, quivering in the extremities, and a heightened sense of impending death. Tandy, perhaps inspired by the late hour and solitude, had made the intellectual leap to an explanation by ghostly means.

I do remember being told that a "whistle" was tried in WWI that could kill with sound. Problem was, it kills the operator too!

This link has some interesting info on "infrasound" you all might find it interesting. Course you never know with sources on the net, but this one has the ring of truth to it. http://www.borderlan...ch/gavreaus.htm

Could a haunting sometimes be caused by something focusing infrasound waves? maybe.................. :-/

Let me preface this with "I'm not an expert but" it doesn't sound like it's anything that's paranormal. It sounds more like a physiological reaction to stimuli. In this case, a frequency of some sort. I'm looking forward to reading what everyone is researching on this stuff.